Method of achieving a permanent &#34;stone-wash&#34; effect on textile fibre materials

ABSTRACT

A method of achieving a permanent stone-wash effect on textile fibre materials, in which method the textile fibre materials are dyed with naphthol dyes and the dyed textile material is then after-treated with a stone-wash finish. Very fast dyeings having a permanent stone-wash finish are obtained.

The present invention relates to a method of achieving a permanentstone-wash effect or “washed-out look” or “used look” on textile fibrematerials, especially cellulosic fibre materials, dyed with naphtholdyes.

In order to impart the “washed-out look” or “used look” to the textilefibre materials, the corresponding textile fibre materials, especiallycotton fabrics, which have generally been dyed with indigo dyes, aresubjected to bleaching, and a so-called “stone wash” process is carriedout in which, for example, pumice stones, pebbles or sand aretraditionally used. A more recent method of achieving the “washed-outlook” or “used look” is distinguished by the use of cellulases(enzymes). In that method, the dyed textile fabric, e.g. jeans, isdesized and then treated with cellulase. The advantage of the enzymaticmethod is that bleaching and the use of, for example, pumice stone areunnecessary.

A major disadvantage of the procedures described above is that theeffect cannot be maintained over a prolonged period because of bleeding,or washing out, and rubbing abrasion of the textile material customarilydyed with indigo dyes as a result of regular domestic washing. Thatdisadvantage is, surprisingly, overcome with the method according to theinvention. The method according to the invention is a method ofachieving a permanent stone-wash effect, in which the textile fibrematerial, especially cellulosic fibre material, is dyed in the desiredcolour shade with naphthol dyes and then after-treated with a stone-washfinish.

The textile fibre material used in the method according to the inventionis preferably cellulosic fibre material, especially cotton.

Very special preference is given to the use of denim in the methodaccording to the invention. Denim is a cotton material with generally ablue-dyed warp and natural white weft. The warp is preferably dyed inthe size (e.g. blue jeans).

The naphthol dyeings produced by the method according to the inventionare produced on the fibres by combining (coupling) two solublecomponents, a naphtholate and a diazotised base. The base is eitherproduced in the dyehouse itself or is purchased in the form of astabilised diazotised fast-colour base, a so-called dyeing salt, from adye manufacturer. There are a large number of combinations with which,for example, vivid yellow, orange and red shades can be achieved, whichcannot be produced with the indigo dyes. Of course, all the blue shadescan also be achieved with the naphthol dyes. The naphthol dyes aredistinguished by good fastness properties, especially fastness toboiling. The dyeings achieved in accordance with the method according tothe invention are further distinguished by excellent fastness tochlorine. It is to be emphasised that a broad spectrum of colour shadesis opened up by the method according to the invention. In comparisonwith the indigo dyes, which subsequently bleed with every domestic washand consequently do not allow a permanent effect, e.g. the stone-washeffect, to be obtained, the naphthol dyeings achieved using the methodaccording to the invention do not exhibit any bleeding of the dye.

Furthermore, in comparison with the products dyed with indigo dyes, thedyeings, or dyed and made-up textiles, produced in accordance with themethod according to the invention can better be provided with a finish,for example a finish comprising synthetic resins for imparting aneasy-care finish to the fabric, and/or a Teflono finish for imparting awater-, oil- and dirt-repellent finish to the fabric. A further finishwhich is of interest is finishing with emery machines in order to imparta velour leather character to the fabric, for example by means of emeryrollers, that effect being achieved by grinding and accordinglysplitting open the ends of the fibres.

Textile finishes as indicated above are described, for example, inEP-A-1 088 867, EP-A-1 225 269, EP-A-1 236 783, WO 86/02115, EP-A-0 325918, EP-A-0 459 125, EP-A-0 491 248, EP-A-0 073 364.

When producing a naphthol dyeing, attention must be given to thestoichiometric calculation of the developer component (diazo componentor fast-colour dyeing salt or fast-colour dye base) and the couplingcomponent (substrate is impregnated with the coupling component), whichcouple together to form a depth of shade which is given in grams offixed naphthol per kilogram of product (textile fibre material). Thedissolution specifications for naphtholates and fast-colour dyeing saltshave to be met precisely. Naphthols can be applied in the exhaust or padprocess, the two-bath procedure, i.e. separate impregnation anddeveloping, being the method customarily employed. In the exhaustprocess, the liquor ratio has to be adhered to precisely, because theproportion of the coupling component taken up by the fibres determinesthe depth of shade. In order to remove excess naphtholate after theimpregnation, squeezing off, centrifuging off or rinsing areadvantageously carried out. For denim articles it is usual to impregnatewarp yarns in the size with naphthols. In order to develop the naphtholdye in the various procedures, a boiling bath comprising soap or specialdispersants has proved advantageous.

The following may be mentioned as examples of naphtholates forimpregnation, the C.I. number according to Colour Index, The Society ofDyers and Colourists, American Association of Textile Chemists andColourists, Third Edition, Volume 4, 1971 also being given in additionto the formula for the purpose of characterisation:

Further naphtholates or coupling components for impregnation which canbe used in the method according to the invention are described, forexample, in Colour Index, The Society of Dyers and Colourists, AmericanAssociation of Textile Chemists and Colourists, Third Edition, Volume 4,1971. Examples which may be mentioned include the azoic couplingcomponents of the formulae having the C.I. numbers 37500, 37510, 37511,37516, 37521, 37525, 37526, 37527, 37532, 37535, 37540, 37545, 37550,37558, 37559, 37560, 37565, 37566, 37567, 37568, 37569, 37570, 37575,37580, 37585,37590, 37595, 37600, 37605, 37608, 37610, 37611, 37613,37614, 37615, 37620 and 37625.

As diazotised fast-colour bases, or so-called dyeing salts, there comeinto consideration, for example, the following salts, the C.I. numberaccording to Colour Index, The Society of Dyers and Colourists, AmericanAssociation of Textile Chemists and Colourists, Third Edition, Volume4,1971 also being given in addition to the formula for the purpose ofcharacterisation:

Further diazotised fast-colour bases or dyeing salts which can be usedin the method according to the invention are described, for example, inColour Index, The Society of Dyers and Colourists, American Associationof Textile Chemists and Colourists, Third Edition, Volume 4, 1971.Examples which may be mentioned include the diazotised fast-colour basesor dyeing salts of the formulae having the C.I. numbers 37020, 37025,37030, 37035, 37045, 37050, 37055, 37060, 37065, 37070, 37075, 37077,37080, 37085, 37090, 37095, 37100,37105,37107, 37110,37111,37112,37115,37120,37130, 37135,37136,37140, 37145, 37150,37151,37155,37160,37161,37165, 37170,37175,37180, 37190,37195, 37200, 37205, 37210,37215, 37220, 37225, 37235, 37240,37245, 37250, 37255, 37260, 37265,37270 and 37275.

In a preferred embodiment of the method according to the invention, thewarp yarn is impregnated with a naphtholate and then interwoven withnatural white cotton yarn, the colour is then developed on the fabricwith the addition of a diazo salt, and the dyed fabric, advantageouslyafter being made up, e.g. in the form of jeans, is after-treated with astone-wash finish.

In a very especially preferred embodiment of the method according to theinvention, the cotton warp yarn is impregnated with a naphtholate as thecoupling component, it being possible for the impregnationadvantageously to be carried out in the size, and then interwoven withnatural white cotton yarn, the colour is then developed on the fabricwith the addition of a diazo salt, the dyed fabric is made up, and themade-up article is then after-treated with a stone-wash finish.

In a very especially important procedure of the method according to theinvention, the cotton warp yarn is impregnated with a naphtholate duringthe sizing treatment and is then interwoven with natural white cottonyarn, the colour is then developed on the fabric with the addition of adiazo salt, the dyed fabric is made up, and the made-up article is thenafter-treated with a stone-wash finish.

Sizing is carried out by processes known per se. The essence of sizingconsists in passing the warp threads through a dispersion of, forexample, swollen starch or another adhesive agent, e.g. glue orcellulose ether, so that the individual fibres of which the thread iscomposed are intimately bonded to one another and, especially, the fibreends standing out from the surface of the yarn are bonded to the core ofthe thread. As a result, the thread acquires greater resistance totearing and resistance to abrasion, so that the weaving process is lessoften subject to interruption owing to breakage of the warp thread.Sizing is comprehensively described in the literature, for example inLehrbuch der Textilchemie by Hermann Rath, 2nd Edition 1963, SpringerVerlag, Berlin, Göttingen, Heidelberg, pages 45 and 203 ff and inLexikon for Textilveredlung by H. K. Rouette, Volume 3, 1995,Laumann-Verlag Dülmen, pages 1890 ff. Examples of sizing agents thatcome into consideration include water-soluble sizing agents, especiallynatural products based on starch or albumen, as well as sodium alginate.Also suitable are synthetic products, such as vinyl derivatives,especially polyvinyl alcohols and also polyvinyl alcohols partiallyhydrolysed by the CH₃—CO—O— group, for example, and polyacrylicderivatives as well as mixtures of the various sizing agents. There maybe mentioned as a sizing formulation, for example, the dispersion of astarch, e.g. of amylose. The starch may also be modified, in which casethe free OH groups are modified by CH₃—CO—, —CH₂—COOH or —CH₂—CH₂—OH.Typical commercially available sizing agents based on polyacrylicderivatives are, for example, Ciba® VICOL® WLV, Ciba® VICOL® WNR, sizeCA (BASF). A typical commercially available sizing agent based onpolyvinyl alcohol is, for example, size UC-1 (BASF). Typicalcommercially available sizing agents based on starch or modified starchare, for example, SOLAMYL, AMITROLIT, Polyamyl, Extrasize CM. The sizingagents can be used together with a softener or a lubricant, for exampleCiba® ALCOWAX®SB, Ciba® ALCOWAX® OG, Basasoft LB 394.

For the stone-wash finish it is especially preferred for the effect tobe achieved by washing with stones or sand.

For the stone-wash finish it is likewise especially preferred for theeffect to be achieved by enzymatic after-treatment.

The stone-wash after-treatment can be carried out in customary manner,as described, for example, in DE-C1-36 42 593, WO 90/02790, WO 95/09225or WO 01/57173. For example, 60 kg of blue jeans material (denim) arewashed at from 60 to 70° C. for 60 minutes in a commercially availablewashing machine together with 60 kg of aerated concrete stones, waterand a commercially available washing agent. After washing, the materialso treated is freed of the washing agent and the stones by rinsing. Thedried material is markedly lighter in colour after the treatment andexhibits the desired “stone-wash” effect.

The colour washed out of and rubbed off the textile fibre material bythe stone-wash finish can be treated by the renewed application ofcolour, especially by dyeing or spraying, so that different colourshades or colour progressions are obtained on the fibre material.

In a preferred embodiment of the further subsequent application ofcolour, the colour shade achieved by the application of colour isdifferent from the base colour obtained with the naphthol dye.

The invention relates also to the use of naphthol dyes in producing adenim finish for achieving the stone-wash-finish effect.

There come into consideration as textile fibre materials especiallyhydroxyl-group-containing fibre materials. Preference is given tocellulosic fibre materials which consist wholly or partially ofcellulose. Examples are natural fibre materials, such as cotton, linenor hemp, and regenerated fibre materials, e.g. viscose and also lyocell.Special preference is given to viscose or especially cotton or veryespecially denim. Other fibre materials which may be mentioned are wool,silk, polyamide and aramid. The mentioned fibre materials are preferablyin yarn form.

The dyeings obtained by the method according to the invention have verygood fastness to light and good fastness-to-wetting properties, such asfastness to washing, water, seawater, crossdyeing and perspiration.Special mention is to be made of the very good fastness-to-wettingproperties, such as fastness to boiling, and the excellent fastness tochlorine.

The Examples which follow are intended to illustrate the invention butdo not limit the invention to the specific Examples.

EXAMPLE 1 Production of a Dark-blue Naphthanilide Dyeing on 100 % of aCotton Warp Yarn and Subsequent Interweaving with Natural White CottonWeft Yarn

A solution for impregnation of the warp yarn is prepared as follows:

Solution 1: The following are dissolved in 27 litres of water at 75° C.:

20 g/l of naphthanilide RC of formula (1)

10 g/l of a protective colloid, e.g. IGRASOL® DN

0.3 g/l of a deaerating agent, e.g. ALBATEX® FFC

0.2 g/l of a wetting agent, e.g. CIBAFLOW® PAD.

The solution is made up to 40 litres.

A sizing formulation, solution 2, is prepared by dissolving

133.4 g/l of a modified starch, e.g. Polamyl or Extrasize CM

10.0 g/l of a softener, e.g. Basosoft LB 394

in 45 litres of water at 90° C. and is then made up to 60 litres.

Solution 1 and solution 2 are mixed and fed to the sizing machine.Impregnation is carried out at about 92° C, the speed is 35 m/minute,the liquor pick-up is about 100%. After drying, the moisture content isabout 8% by weight and the dry content of the size in the yarn is 5.6%by weight.

The impregnated cotton warp yarn is then interwoven with natural whitecotton weft yarn. A total of 3750 m of cotton warp yarn are processed,which results in the production of 2900 m of fabric. The fabric obtainedhas a weight per metre of 636 g at a width of 1.5 m.

A dark-blue shade on 700 m of the fabric is developed as follows:

100 g/l of diazo fast-colour blue VBN of the formula

and 6.5 g/l of a dispersant, e.g. IRGASOL® NA, are dissolved while coldin 40 litres of water. Impregnation is carried out in a padding machinewith a liquor pick-up of about 70% and a speed of 30 m/minute. Afterrinsing and soaping of the developed dyeing in a continuous washinginstallation and subsequent drying of the dyed fabric, a dark-bluedyeing is obtained.

The dyed fabric so obtained is made up into jeans (further possibilitiesare making up into articles of clothing such as e.g. shirts or jackets).

The “stone-wash effect” is then imparted to the dyed and made-up articleof clothing in a washing process, as follows:

In a commercially available washing machine, 10 kg of the jeans (denim)dyed blue in the manner indicated above are washed at from 60 to 70° C.for 60 minutes together with 10 kg of aerated concrete stones, 40 litresof water and a commercially available washing agent. The jeans sotreated are then rinsed in order to remove the washing agent and thestones, and then dried. The dried jeans are markedly lighter in colourafter the treatment and exhibit the desired “stone-wash” effect.

The effect is maintained unchanged even after several domestic washes,because no further dye bleeds from the jeans.

If the procedure of Example 1 is followed but, in an otherwise identicalprocedure, there is used Instead of naphthanilide RC an equimolar amountof one of the coupling components listed In Table 1, column 2, togetherwith one of the diazo fast-colour bases listed in Table 1, column 3, inan equimolar amount, textiles dyed in the given shade (see column 4) areobtained which exhibit the desired stone-wash effect and which do notbleed further in subsequent washes and which exhibit excellent fastnessproperties. TABLE 1 Coupling component or Shade on Example naphtholateDiazo fast-colour base or dyeing salt cotton 2

scarlet 3

blue 4

claret 5

red 6

black 7

orange 8

red 9

claret 10

red 11

scarlet 12

black 13

black

1. A method of achieving a permanent stone-wash effect on a textilefibre material, in which the textile fibre material is dyed with anaphthol dye and the dyed textile fibre material is then after-treatedwith a stone-wash finish.
 2. A method according to claim 1, in which thetextile fibre material is cellulosic fibre material.
 3. A methodaccording to claim 2, in which denim is used.
 4. A method according toclaim 1, in which a warp yarn is impregnated with a naphtholate and theninterwoven with natural white cotton yarn, the colour is then developedon the fabric with the addition of a diazo salt, and the dyed fabric isafter-treated with a stone-wash finish.
 5. A method according to claim1, in which a cotton warp yarn is impregnated with a naphtholate andthen interwoven with natural white cotton yarn, the colour is thendeveloped on the fabric with the addition of a diazo salt, the dyedfabric is made up and the made-up article is then after-treated with astone-wash finish.
 6. A method according to claim 1, in which a cottonwarp yarn is impregnated with a naphtholate during a sizing treatmentand then interwoven with natural white cotton yarn, the colour is thendeveloped on the fabric with the addition of a diazo salt, the dyedfabric is made up and the made-up article is then after-treated with astone-wash finish.
 7. A method according to claim 1, in which thestone-wash finish is achieved during washing with stones or sand.
 8. Amethod according to claim 1, in which the stone-wash finish is producedby enzymatic after-treatment.
 9. A method according to claim 1, inwhich, following the stone-wash finish, a further dye is applied to thedyed and treated fabric.
 10. A method according to claim 9, in which theapplication of colour is effected by dyeing or spraying.
 11. A methodaccording to claim 9, in which the application of colour yields a colourshade that is different from the base colour obtained with the naphtholdye.
 12. (canceled)
 13. A method according to claim 1, in which thetextile fibre material is cotton.